1. Field of the Invention
The present invention relates to a flying type thin film magnetic head provided with a reading/writing element at an end surface of a slider. More particularly, it relates to a flying type thin film magnetic head wherein the surface which opposes a magnetic medium, of the slider is flat and without rail portions each provided with a tapered portion at its one end.
2. Discussion of Background
There has been known, for a magnetic disk drive, a flying type thin film magnetic head which floats with a space by a minute air bearing to a magnetic recording medium by utilizing a dynamic pressure resulted when the magnetic recording medium is moved. Such flying type thin film magnetic head is disclosed in U.S. Pat. Nos. 4,130,847, 4,218,715 and 4,219,853. Namely, the basic construction of the conventional magnetic head is such that two rail portions are formed with a space therebetween at a surface of a slider made of ceramics which opposes the magnetic recording medium so that the surface between the rail portions functions as an air bearing surface, and a tapered portion is formed at each one end (at the air intake side) of the rail portions so that a lifting force is produced at the tapered portions in association with the magnetic recording medium. The reading/writing element is a thin film magnetic head element prepared in accordance with the same process as an IC manufacturing technology, and the reading/writing element is formed or attached at the air discharging side which opposes the tapered portions of the slider.
In the thin film magnetic head of this kind, there is a trend of miniaturization in order to comply with a demand of high density and high speed magnetic recording. The miniaturization of the thin film magnetic head is effective to reduce a flying height necessary for the high density recording and to reduce a spacing loss. Further, it is advantageous to increase the resonance frequency in association with a gimbal device, to eliminate crashing and to improve durability. In addition, an appropriate balance is obtainable between the dynamic pressure and the pressure of a supporting spring and the posture of the magnetic head can be properly maintained, whereby a stable flying characteristic can be obtained. Further, reduction in the mass of the magnetic head obtained by the miniaturization increases the speed of accessing movement of an arm for supporting the gimbal device.
It is, however, difficult to reduce the size of the conventional flying type thin film magnetic head because it has a complicated structure such that the rail portions and the tapered portions are provided at the surface of the slider opposing the magnetic recording medium. To solve this problem, there was proposed a thin film magnetic head wherein the surface of the slider opposing the magnetic recording medium is made flat without forming the rail portions (e.g. in U.S. Pat. No. 4,803,577). FIG. 8 is a perspective view of such thin film magnetic head of the above-mentioned type. In FIG. 8, a reference numeral 1 designates a slider, a numeral 2 designates a reading/writing element and numerals 3, 4 designate bonding pads. The slider 1 has a medium-opposing surface 101 which is made flat without forming rail portions and tapered surfaces for producing a floating force, and the opposing surface 101 functions, as a whole, as an air bearing surface.
The reading/writing element 2 is attached to an end surface of the slider 1 which is an end in the direction of air discharging in combination with the magnetic recording medium. The reading/writing element 2 used is a single which is disposed around an intermediate portion in the width direction of the slider 1.
The bonding pads 3, 4 are connected to both ends of a conductor coil film which constitutes the reading/writing element 2.
In a case that the magnetic head is used in a magnetic disk drive, it is driven by a so-called contact.start.stop method wherein the surface 102 opposite the medium-opposing surface 101 is attached to a magnetic head supporting device (a gimbal device) (not shown) while the medium-opposing surface 101 is brought into in spring-contact with the surface of the magnetic disk, and starting and stopping are carried out in this state. When the magnetic disk is in a stationary state, the medium-opposing surface 101 is pushed to the surface of the magnetic disk by the spring action of the magnetic head supporting device. However, when the magnetic disk is rotated, a dynamic pressure for floating the slider 1 to the medium-opposing surface 101 is produced, whereby a flying height obtained by balancing the dynamic pressure and the spring pressure of the magnetic head supporting device is provided.
Since the thin film magnetic head as shown in FIG. 8 is provided with the medium-opposing surface 101 in the slider 1 which is simply flat without rail portions, it is possible to reduce the size of the magnetic head to thereby assure the above-mentioned advantage.
However, the above-mentioned thin film magnetic head had the following problems.
(a) A recess may be produced at an intermediate portion in the width direction of the medium-opposing surface 101 due to deformation in a workpiece during machining operations in order to produce the slider, as illustrated in FIG. 9 with a great exaggeration. When such a recess is produced in the medium-opposing surface 101, a proper contact of the magnetic head to the magnetic disk can not be obtained, whereby a spacing loss becomes large and head-crashing may be easily caused. The durability of the magnetic head is also reduced.
(b) Since the shape of the slider is cubic as a whole, when the surface area of the medium-opposing surface 101 is reduced, the surface area of the surface 102 opposite the medium-opposing surface 101 is also reduced. Since the surface 102 constitutes a portion to which a magnetic head supporting device is attached, reduction in the surface area 101 also invites reduction in the surface area of the surface area 102 to which the magnetic head supporting device is attached. Accordingly, as the size of the slider 1 is miniaturized, it becomes difficult to attach the magnetic head supporting device.